In a series of blog posts, I will go over each of the Cisco’s official blueprint sections for CCIE SP 400-201 V4.1 written exam and call out the very essential topics and knowledge base that are must-know for passing the exam. Please note that all of our CCIE Written Exam Cert Study Guides include similar exam essentials at the end of each chapter to reinforce key concepts for our readers.

I hope that you find them useful!

While a PE router maintains VPN routing information, it is only required to maintain VPN routes for those VPNs to which it is directly attached.

P routers are only required to maintain routes to the provider’s PE routers; they are not required to maintain a specific VPN routing information for each customer site.

The IOS-XR Microkernel is preemptive, and the scheduler is priority based

The following are the main functions of IOS-XR system manager:

Start processes during bootup or node reload

Start processes during route processor (RP) failover

Start processes in response to user configuration; for example, when a user configures an OSPF process using router ospf <process-name>, system manager starts a new OSPF process instance

Act as a central repository for all process-related information

Initiate disaster recovery based on the process health

Invoke dumper to collect a core dump when a process terminates abnormally